The present invention relates generally to electronic ballasts. More particularly, the current invention relates to ballasts and ballast housings having an integral ground for a circuit board positioned within the ballast housing.
Ballast housings having electronic components, including circuit boards, positioned in the housings are well known in the art. These circuit boards are normally attached by screws or other fasteners to the metal housing and include a soldered, insulated lead wire extending from the plane of the circuit board and connected to a slot, or opening, in the canned portion of the metal housing. This lead wire is usually stripped to bare wire at the point it is connected to the metal can.
This type of grounding for circuit boards taught by the prior art has several disadvantages, including the need to maintain a separate wiring inventory for each component that goes into the ballast housing. There are also additional manufacturing labor costs associated with the soldering the lead wire to the circuit board and then soldering or fastening the other end of the lead wire to the housing. Injuries to workers assembling circuit boards in the ballast housings are associated with the prior art installation process. Additionally, the soldered connections and fastener connections between the lead wire and the circuit board and between the lead wire and the ballast housing are more susceptible to manufacturing defects because of the manual or semi-automated processes associated with assembling the ballast of the prior art and are a common failure point in the electrical circuit in which the circuit board is operating.
For example, the prior art uses both soldered connections and screw type fasteners in assembling the ballast. Both fastening means requires multiple steps and slows the installation process of mounting the circuit board into the ballast housing, thus increasing per unit labor costs and reducing throughput. The solder components and screw type fasteners must also be maintained and controlled as separate inventory items, which further increases manufacturing overhead costs. Both soldered connections and screw type fasteners are associated with circuit failures. These disadvantages in the design of prior art ballast housings create additional costs in the manufacture of the ballast housing, as well as increase safety issues during the assembly of the ballast housing.
What is needed, then, is a ballast housing having features that are integral to the housing and that receive and secure a circuit board within the housing and provide electrical continuity between a grounding means disposed on the circuit board and the housing without the need of installing separate lead wires. This needed ballast housing would most desirably include a quick assembly, ‘snap in’ connection between the printed circuit board, the ballast housing, and the integral grounding device.